I. Field of the Invention
This invention relates generally to electrosurgical instruments, and more particularly to a bipolar electrosurgical forceps cauterization instrument specifically designed for use in the performance of percutaneous laparoscopic cholecystectomy or similar endoscopic procedures.
II. Discussion of the Prior Art
Heat has been used for the cauterization of bleeding wounds for centuries. Recently, the use of radio frequency (RF) energy travelling through the body has been widely used to stop bleeding. The RF energy cauterizes the blood vessels by heating proteins in the blood to a temperature where the proteins congeal. RF energy is preferred because its frequency is above that which could otherwise cause neuro-muscular stimulation. At least two modes of RF cauterization are typically employed, namely monopolar or bipolar coagulation.
A monopolar electrosurgical system usually consists of an RF generator unit, an active electrode of small dimensions, and a large area return or dispersive electrode designed to be placed on the patient's buttocks or thigh to serve as a return point for the RF energy released at the active electrode site. The active electrode is applied to the bleeding site and the current path is completed through the body to the return electrode which is electrically in contact with the buttocks or thigh. One technique in which the monopolar mode may be employed involves fulguration which is the use of a spark or arc from the active electrode to the tissue.
Bipolar electrosurgical devices have the inherent advantage over monopolar devices of containing the RF energy. In a bipolar device, both the active and the return electrodes are placed on the surgical instrument. Thus, no separate return electrode on the patient is required as in monopolar systems. The RF energy remains at the site where the device is being used and only affects patient tissue in close proximity. Generally, bipolar devices are able to achieve the same results as competing monopolar devices while using a lower level of RF energy. Potential patient complications related to monopolar RF energy travelling through the body on a somewhat unpredictable path to the return electrode are avoided.
The conventional treatment for a diseased gall bladder has been a total cholecystectomy involving cutting a fairly large incision through the abdominal wall and, using a scalpel, to dissect the gall bladder from its bed and to cut a cystic artery and cystic duct to thereby release the organ and allow it to be extracted through the incision. According to National Inpatient Profile, Health Care Knowledge Systems, Ann Arbor, Mich., 1989: 360, the average post operative stay following gall bladder removal surgery of this type in 1988, on a nationwide basis, was 6.1 days and full recovery to normal activities required four to six weeks recuperation.
A relatively new procedure referred to as "laparoscopic laser cholecystectomy" has been devised and it is significantly less invasive than the heretofore conventional approach for gall bladder removal. Rather than working through a major incision in the abdominal wall, a first small puncture wound is made in the umbilicus. A needle is inserted and a pneumoperitoneum is established with CO.sub. 2 gas to distend the abdomen. Next, a trocar and cannula are inserted through the umbilical incision and following removal of the trocar, a diagnostic laparoscope is inserted. Rather than direct visualization through the laparoscope, the scene may be viewed on a CRT screen.
Upon proper observation of the peritoneal cavity, three additional incisions are made at predetermined locations and cannulas are inserted. The lumens and the cannulas are sufficiently large to permit surgical instruments to be inserted therethrough. The instruments generally include a grasping forceps, a clip plier for ligating the cystic duct and cystic artery, a microscissors and a coagulating or cauterizing instrument. A flexible, fiber-optic rod coupled to the output of the laser is used to effect hemostatic cutting and vaporization.
The percutaneous laparoscopic procedure allows total removal of the gall bladder through the larger cannula. Following the surgery all that is required is a single stitch in the umbilicus and the use of sterile adhesive strips for closing the other three wounds. Using this procedure, the hospital stay has been reduced to less than one day and the period for total recovery and resumption of normal activities is reduced to about 4 days. Moreover, scarring is minimal.
In the past, to cauterize blood vessels during the percutaneous laparoscopic cholecystectomy, either the cutting laser was used for small bleeding blood vessels, or a monopolar cauterization instrument was used for larger bleeders. These methods, however, have two significant drawbacks. Monopolar instruments, using RF energy, often have an unpredictable current flow path back to the return electrode. This unpredictable current flow may have a destructive effect on tissues surrounding the cystic duct or the cystic artery. While non-contact positioning of a bipolar laser may overcome this problem, the laser has no way of holding a bleeding vessel and is not used on larger bleeders. The invention described herein overcomes both of these drawbacks, by utilizing bipolar energy applied to a rotatable forceps that can hold a bleeding blood vessel or vessels.
U.S. Pat. No. 4,005,714, entitled "Bipolar Coagulation Forceps", describes an arrangement in which the forceps is designed to occlude both the fallopian tube and the adjacent mesosalpinx. The forceps embodies two insulated current conductors terminating in a coaxial plug and a coaxial contact bushing. The conductors may be opened and closed by shifting an outer actuating sleeve with the aid of a handle that is stationary in relation to the forceps' arms. The device moves the outer sleeve translationally in relation to the inner stationary sleeve and forceps device. In contrast, in the invention yet to be described herein an inner tube moves translationally within a stationary outer tube. The device of the '714 patent also differs from the current invention in that it has no means built into the handle for permitting rotation of the forceps' jaws or pinchers at the distal end of the tubes without turning the entire device and no means for introducing a preset gap between the forceps' jaws. The invention described herein incorporates the flexibility of a rotating forceps at the distal end of the tubes, while holding its handle stationary, to thereby better facilitate grasping bleeding blood vessels. The invention allows introduction of a present gap between the forceps' jaws to preclude shorting of the leads at the distal end and give better control over cauterization of bleeding tissues.
U.S. Pat. No. 3,920,021 describes devices for coagulating animal tissue by means of high frequency current. The device, as depicted, appears to show bipolar electrodes at the distal end of an outer tube. The proximal end of the outer tube and the proximal end of the inner tube are attached to a squeezable device that will move both the outer tube and the inner tube. Hence, neither the outer tube nor the inner tube is translationally stationary in relation to the handle. The device described in the '021 patent does not contain a means for rotating the forceps at the distal end while holding the handle stationary or means for introducing a preset gap between the forceps' jaws. As such, it is less than satisfactory for laparoscopic procedures.
From the above analysis, it can be seen that the prior art references, individually and as a whole, do not disclose a bipolar electrosurgical forceps cauterizing instrument for use in percutaneous laparoscopic cholecystectomy procedures having rotatable pinching electrodes, an inner tube which moves translationally in respect to a translationally stationary outer tube and handle mechanism or a trigger means for quickly and easily introducing a preset gap between the forceps' jaws.